Evidence Found of How
Vitamins Prevent Cancer
Vitamin E protects against at least
two common forms of cancer -- prostate and bladder -- but popping
supplements is probably not the best way to get the vital nutrient,
Two studies found that people who
either ate the most vitamin E containing food or who had the highest
levels in the blood were the least likely to have cancer.
But the researchers also noted
that there are several different forms of vitamin E and the kind
you eat -- in this case alpha tocopherol -- is key. And the best-absorbed
form of alpha tocopherol is not found in supplements but in foods
such as sunflower seeds, spinach, almonds and sweet peppers.
In one of the studies presented
to the annual meeting of the American Association of Cancer Research
in Orlando, Stephanie Weinstein of the U.S. National Cancer Institute
and colleagues found men with the most vitamin E in their systems
had the lowest risk of prostate cancer.
They looked at data from 29,133
Finnish men aged between 50 and 69 taking part in a smoker's study.
All gave blood at the beginning of the study and then took vitamins
to see whether the supplements might prevent various forms of
This study is best known for showing
that smokers who took beta carotene, which the body converts to
vitamin A, actually had higher rates of lung cancer.
Weinstein looked at vitamin E and
prostate cancer, and they looked at how much E the men had in
their blood before they ever took a supplement. They looked at
100 men with prostate cancer and 200 men who did not.
"We found that the men who had
higher serum (blood) levels of vitamin E had a lower chance of
getting prostate cancer," Weinstein told a news conference monitored
NOT ALL E'S ARE EQUAL
Then they looked at the two main
forms of vitamin E -- alpha tocopherol and gamma tocopherol.
Men with the highest natural levels
of alpha tocopherol were 53 percent less likely to later develop
prostate cancer. Men with the highest levels of gamma tocopherol,
which only represents about 20 percent of the vitamin E in blood
-- had a 39 percent lower chance.
Taking supplements further reduced
prostate cancer rates.
"Nuts and seeds, whole grain products,
vegetable oils, salad dressings, margarine, beans, peas and other
vegetables are good dietary sources of vitamin E," Weinstein said.
In a similar study, Dr. Xifeng
Wu of the University of Texas M.D. Anderson Cancer Center, John
Radcliffe of Texas Woman's University in Houston and colleagues
studied 468 bladder cancer patients and 534 cancer-free volunteers.
They asked their 1,000 volunteers
what they ate, and estimated how much alpha-tocopherol and how
much gamma tocopherol they got in their everyday diets and from
supplements if they took them.
Those with the highest intake of
alpha tocopherol from food had a 42 percent reduced risk of bladder
cancer, and those who had a vitamin E-rich diet and took supplements
too had a 44 percent lower risk.
But when broken down into types,
they found gamma tocopherol offered no protection against bladder
"It would not be reckless to encourage
people to try and meet the dietary allowance of vitamin E, which
is about 50 milligrams a day," Radcliffe told the news conference.
Current average U.S. intake of E is only 8 mg a day.
One of the best sources, said Radcliffe,
a dietician, is a handful of sunflower seeds. Almonds, spinach,
mustard greens and green and red peppers are also good sources
of alpha tocopherol.
Many E supplements, he said, contain
both active and inactive forms of E and may not be the best source.
Plus, he said, sunflower seeds are high in selenium, another key
nutrient, while greens are loaded with desirable nutrients.
Reference Source 89